Web Programming with Python and JavaScript

SQL, Models, and Migrations

Data

origin destination duration

New York London 415

Shanghai Paris 760

Istanbul Tokyo 700

New York Paris 435

Moscow Paris 245

Lima New York 455

SQL

Database Management Systems

• MySQL

• PostgreSQL

• SQLite

• ...

SQLite Types

• TEXT

• NUMERIC

• INTEGER

• REAL

• BLOB

MySQL Types

• CHAR(size) • VARCHAR(size) • SMALLINT • INT • BIGINT • FLOAT • DOUBLE • ...

CREATE TABLE

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

CREATE TABLE flights ( id INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT NOT NULL, destination TEXT NOT NULL, duration INTEGER NOT NULL );

Constraints

• CHECK • DEFAULT • NOT NULL • PRIMARY KEY • UNIQUE • ...

INSERT

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

INSERT INTO flights (origin, destination, duration) VALUES ("New York", "London", 415);

SELECT

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT origin, destination FROM flights;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT origin, destination FROM flights;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE id = 3;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE id = 3;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin = "New York";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin = "New York";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500;

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500 AND destination = "Paris";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500 AND destination = "Paris";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500 OR destination = "Paris";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE duration > 500 OR destination = "Paris";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin IN ("New York", "Lima");

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin IN ("New York", "Lima");

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin LIKE "%a%";

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

SELECT * FROM flights WHERE origin LIKE "%a%";

Functions

• AVERAGE • COUNT • MAX • MIN • SUM • ...

UPDATE

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

UPDATE flights SET duration = 430 WHERE origin = "New York" AND destination = "London";

DELETE

DELETE FROM flights WHERE destination = "Tokyo";

DELETE FROM flights WHERE destination = "Tokyo";

DELETE FROM flights WHERE destination = "Tokyo";

DELETE FROM flights WHERE destination = "Tokyo";

DELETE FROM flights WHERE destination = "Tokyo";

Other Clauses

• LIMIT • ORDER BY • GROUP BY • HAVING • ...

Foreign Keys

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

flights

id origin origin_code destination destination_code duration

1 New York JFK London LHR 415

2 Shanghai PVG Paris CDG 760

3 Istanbul IST Tokyo NRT 700

4 New York JFK Paris CDG 435

5 Moscow SVO Paris CDG 245

6 Lima LIM New York JFK 455

flights

id code city

1 JFK New York

2 PVG Shanghai

3 IST Istanbul

4 LHR London

5 SVO Moscow

6 LIM Lima

7 CDG Paris

8 NRT Tokyo

airports

id origin destination duration

1 New York London 415

2 Shanghai Paris 760

3 Istanbul Tokyo 700

4 New York Paris 435

5 Moscow Paris 245

6 Lima New York 455

flights

id origin_id destination_id duration

1 1 4 415

2 2 7 760

3 3 8 700

4 1 7 435

5 5 7 245

6 6 1 455

flights

id first last flight_id

1 Harry Potter 1

2 Ron Weasley 1

3 Hermione Granger 2

4 Draco Malfoy 4

5 Luna Lovegood 6

6 Ginny Weasley 6

passengers

id first last

1 Harry Potter

2 Ron Weasley

3 Hermione Granger

4 Draco Malfoy

5 Luna Lovegood

6 Ginny Weasley

people

person_id flight_id

1 1

2 1

2 4

3 2

4 4

5 6

6 6

passengers

JOIN

first last origin

Harry Potter New York

Ron Weasley New York

Hermione Granger Shanghai

Draco Malfoy New York

Luna Lovegood Lima

Ginny Weasley Lima

SELECT first, origin, destination FROM flights JOIN passengers

ON passengers.flight_id = flights.id;

JOINs

• JOIN / INNER JOIN • LEFT OUTER JOIN • RIGHT OUTER JOIN • FULL OUTER JOIN

CREATE INDEX

CREATE INDEX name_index ON passengers (last);

SQL Injection

Username:

Password:

SELECT * FROM users WHERE username = username AND password = password;

Username:

harry

Password:

12345

SELECT * FROM users WHERE username = username AND password = password;

SELECT * FROM users WHERE username = "harry" AND password = "12345";

Username:

hacker" --

Password:

SELECT * FROM users WHERE username = username AND password = password;

SELECT * FROM users WHERE username = "hacker"--" AND password = "";

SELECT * FROM users WHERE username = "hacker"--" AND password = "";

Race Conditions

Models

SQL, Models, and Migrations

Web Programming with Python and JavaScript